In order to pick up harvested crops, combines are fitted with cutting units which are equipped with cutter bars for cutting the crop, a reel which is arranged above the latter and rotates during operation, and a transverse conveying device in the form, for example, of a worm or a plurality of conveying belts. During operation, the reel presses the crop rearwards and downwards opposite to the forward direction in order to make it easier to cut the plants with the cutter bar. Besides mechanical drives, hydraulic drives for the reel are also known.
Furthermore, many combines are equipped with pairs of chaff spreaders, which are arranged downstream of the cleaning device with regard to the flow direction of the harvested crop residues and are used to spread the harvested crop residues remaining at the end of the upper sieve, which are substantially chaff and relatively large pieces of straw. These chaff spreaders, too, are usually hydraulically driven. See for example DE 35 44 157 C1.
Usually, the hydraulic reel drive motor is assigned a dedicated pump for driving it. See for example DE 100 12 056 A1. It was also proposed to connect the reel drive motor in series with a hydraulic motor which drives a rotating stem divider. See for example DE 102 06 541 A1. It was also proposed to connect the reel drive motor in series with hydraulic motors for driving conveying belts of the cutting unit. See for example EP 1 055 359 A1. Similarly, the hydraulic motors are assigned a dedicated hydraulic pump for driving the chaff spreader.